Armatalona gen. n. – a new genus of subfamily Aloninae (Anomopoda, Chydoridae), separated from genus Alona Baird, 1840

Abstract

The little-known cladoceran Alona macrocopa Sars, 1894 and four related species differ from the majority of the genus Alona by unusual morphology of antenna and postabdomen. Only two species of the five, A. macrocopa Sars, 1894 and A. imitatoria Smirnov, 1989, are found to be valid. The species A. abbreviata Sars, 1895, A. duodontha Henry, 1922 and A. guernei Smirnov, 2001 are proved to be the synonims of A. macrocopa. The detailed morphology of appendages of A. macrocopa and A. imitatoria is studied for the first time. Analysis of morphology of the macrocopa-group reveals numerous characters clearly separating it from other species of Alona despite the wide diversity of this genus. Unusual morphology of the antenna, and the female and male postabdomen does not allow placement of the macrocopa-group in any other genera of Aloninae. So the new genus Armatalona gen. n. is suggested. This new genus is the highly specialized marginal genus of Aloninae, closely related only to the Australian endemic genus Pseudomonospilus Smirnov, 2001. The morphology of Armatalona gen. n. and its place within Aloninae are discussed.